There’s one adjective that comes to mind when people think of Disney: happy. Many USC students still hang on to an affinity for Disney films and visit Disneyland in nearby Anaheim anytime they have a chance.

So what are overgrown Mouseketeers to make of Escape from Tomorrow, an experimental, “guerilla-style” horror movie that was shot on company property without Mickey’s knowledge or consent?

Escape from Tomorrow is a weird, wonderful work of minor-key genius that challenges the entire notion of de rigueur happiness.

Why does it play so well? Maybe because Disney has always had a dark side — it’s been a monolithic fixture in shaping several generations for more than eight decades and its films are home to arguably the most charming stable of villains in modern fiction — and Randy Moore’s movie brings that darkness into the light, kicking and screaming, with style and rough-hewn ingenuity to spare.

Escape from Tomorrow tells the unhappy tale of Jim (Roy Abramsohn), a sympathetic schlub who loses his job — and quite possibly his remaining ties to sanity — during the final hours of a family vacation to Disney World. Suddenly his wife’s (Elena Schuber) gentle nagging turns shrill and hateful. His son (Jack Dalton) and toddler daughter (Katelynn Rodriguez) recoil from his touch, their eyes cold and accusatory. And to make matters worse, he can’t seem to stop himself from obsessively pursuing two underage French girls (Danielle Safady and Annet Mahendru), who flutter through the park like metal-mouthed nymphs, tempting him to recapture his lost youth — a central theme of the film — in the creepiest manner possible.

With its transformative black-and-white photography and the unsettling tagline “Bad Things Happen Everywhere,” Moore’s bizarro version of the Happiest Place on Earth is a grotesque, plastic-fantastic purgatory, where a façade of manufactured mirth masks all manner of nefarious, illegal and possibly even demonic activities, including the sinister machinations of the Other Woman (Alison Lees-Taylor, channeling Grace Zabriskie), the flesh-and-blood equivalent of Snow White’s Wicked Queen.

In order to accentuate this creeping sense of unease, Moore and director of photography Lucas Lee Graham wisely emulate cinematic surrealists such as David Lynch (Mulholland Dr.) and Alejandro Jodorowsky (El Topo), imbuing even the lighter scenes with an undercurrent of monochrome menace, until every familiar sight and sound takes on a grim new significance. For example, Spaceship Earth — better known as the big Epcot golf ball — is revealed as an Orwellian imagination harvesting facility, while the Disney princesses are portrayed as high-end prostitutes who cater to the desires of lascivious Eastern businessmen. And what happens to one unlucky rider on Big Thunder Mountain is a scene better experienced in theaters than written here.

The only thing more outrageous than the movie itself is how it was made. Wary of being discovered during the shoot, Moore and his crew posed as tourists at both Disneyland and Disney World, using handheld video cameras (including the innocent-looking Canon EOS 5D Mark II) and keeping copies of the script on their iPhones. The first-time director, well aware of Disney’s penchant for being extremely protective of its squeaky clean brand image, even arranged to edit the film in South Korea to keep the project under wraps during its lengthy post-production.

Escape from Tomorrow premiered last January at the 2013 Sundance Film Festival, where it became an overnight sensation — though many attendees voiced their doubts that Disney would ever allow the film to be seen or distributed outside of the festival circuit.

The Mouse House has kept mum on Escape from Tomorrow so far, with the exception of a brief, enigmatic entry in the new online edition of Disney A-Z: The Official Encyclopedia. It isn’t clear whether the company would have any legitimate grounds for an intellectual copyright claim. Moore was careful to replace all park music, even the appropriately hellish “It’s A Small World After All,” with original compositions, and his film, an obvious work of satire, technically falls under the provisions of fair use (the same ambiguity that allowed Trey Parker and Matt Stone to write an episode of South Park featuring a foul-mouthed Mickey Mouse beating up the Jonas Brothers).

It would be easy to hear about Escape from Tomorrow and label it sight unseen as an anti-corporate hatchet job, a cynical attempt to shock and subvert. Yet the truth is far more complicated. Moore and his merry band of trespassers have a deeply ingrained affection for Disney; they’re just scared to death of what it’s been doing to us all these years. And that struggle between love and loathing infuses every frame of their audacious creation. As Mickey himself would say, “Oh boy!”